


Grimm Deductions

by A_Winter



Category: Grimm (TV), Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: AO3 FB Challenge, Alternate Universe - Fusion, Crossovers & Fandom Fusions, Gen, M/M, Wesen Character(s)
Language: English
Status: In-Progress
Published: 2018-07-31
Updated: 2018-07-31
Packaged: 2019-06-19 21:45:21
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 4
Words: 3,904
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15519261
Author URL: https://archiveofourown.org/users/A_Winter/pseuds/A_Winter
Summary: Sherlock/Grimm Fusion.Trained from birth to kill rogue Wesen, Sherlock uses his position consulting for the New Scotland Yard to identify Wesen crime and bring justice as only a Grimm can. After all, once a Wesen gives in to their inner beast there is no coming back... is there?X~X~XIt wasn't uncommon for young Wesen to join the military, though in John's case it had been as a doctor not a soldier. Some scorned his decision, until they were bleeding on his table. Captain Watson had quite the reputation while he was serving but reputation alone wouldn't save him or those under his command from the bloodshed and cruelty of war. He'd hoped to outrun his demons by returning to London, however a persistent Grimm was making that impossible.





	1. Damage Control

**Author's Note:**

> Wesen - Pronounced "Vesen" - Were-People  
> Woge - pronounced "Vogue" - The process of transforming  
> Kehrseite – pronounced... not even going there - Non-Wesen numan beings  
> Grimm - One who hunts Wesen, they come from a old family lines and have increased reflexes, strength, healing and the ability to see Wesen for what they are... However this ability often comes after some kind of trauma (like losing a family member) and occurs earlier in women than men. 
> 
> I will do my best to explain the types of Wesen in story but for any fact checking/further info please check out the Grimm Wiki page as that's where I'm getting all my spelling ^_^
> 
> Please enjoy!!!

John looked around the crisp, professional waiting room and sighed heavily as his eyes landed on his next patient. The doctor shared an exasperated look with the medical receptionist, who’d clearly had the pleasure of checking the man in and attempting to once again explain the booking process only to be ignored as usual. John picked up the waiting file and unnecessarily called out in his steady, professional baritone “Sherlock Holmes.”

The man, all long limbs and tailored suit, stood and with an impatient look strode towards John’s office without waiting for directions. The man was becoming an unwelcome regular within the clinic, the nurses gossiped about possible reasons why the tall handsome man might be visiting them so often but unfortunately John knew the truth was not as romantic as their fantasies. 

“Doctor Watson,” Mr Holmes waited until John had closed the door before he spoke, he was leaning casually against the raised procedure bed waiting. 

“Mr Holmes,” John acknowledged with a nod and sigh. “what seems to be the problem today?” 

“The usual Doctor,” Shrugging off his coat, then his jacket the man began to unbutton his shirt but John already had a good idea of what was to come. The doctor had a nose that could not be questioned on these things, and for Mr Holmes this was in fact the usual. 

John didn’t blink at the littering of scars that covered the other man’s chest and back as the shirt was removed, he didn’t even bat an eye at the crudely dressed wound on the man’s shoulder that was bleeding through the dressings and likely had also marked the clothing he’d been wearing. Dark colours however were good for concealing such things from those who are not looking for them. 

“Abartige Aasfresser…” Sherlock answered John’s unasked question, though the Doctor responded to the information with a low whistle. 

“Nasty blighters those, but there’s no accounting for taste…” John chuckled at his own joke as he took out the necessary tools to clean the wound and repair what damage he could. 

As John began to unwind the dressing he shook his head at not only the excessive blood but the use of a less than sterile bandage. 

“Where did you find this, the sewers?” John’s nose crinkled, it certainly smelt that way. 

“Close, back alley. Off the back of a recently deceased Wesen,” John didn’t say anything but the tension was palatable, “his victim not mine.” 

John nodded as the wound was finally revealed, unsurprisingly it was a bite mark over the man’s shoulder. 

“For your sake and mine, I hope he practiced good dental hygiene but I doubt it.” The Hyena like Wesen were scavengers much like their animal kingdom counterparts and not known for cleanliness. 

“From the way his breath smelt, I have bad news for you.” Mr Holmes retorted as John began to clean the jagged, oozing gash. 

“Will that be a problem anymore?” John asked, part of him feeling a deep-seated pleasure at Mr Holmes’ discomfort and pain as the lacerations were cleaned. 

“No.” It was a simply answer but it spoke volumes to John and triggered an instinctive response in the Doctor. 

“…”

“You want to kill me…” came a steady, matter of fact statement. 

“Usually, yes.” John admitted, there was no point lying. “You’re a Grimm and I am Wesen.”

“So?”

“So, you’re out there killing other Wesen and I stitch you up so you can keep doing so. Every instinct I have tells me that I should kill you before you kill me, or more of my kind.”

“But you don’t.” Another statement of fact, though this one blindingly obvious. 

“Indeed.” 

“Why?” John sighed, they’d had this conversation before. Several times in fact but apparently, they were going to have it again. 

“Because I don’t kill, at least not anymore.” John’s mind flashed back to his time in the army, the things he’d done, the lives he’d taken, the overwhelming stench of blood that even managed to turn His stomach. “I save lives, where I can. Wesen and Kehrseite alike. And apparently even the odd Grimm.” 

John began slowly stitching what he could of the wound, a lot of the flesh was missing, luckily for Mr Holmes Grimms healed uncommonly fast for Kehrseite.

“This won’t sustain you for long…”

“Don’t” John barked angrily but, despite how satisfying it would have been to do otherwise, he kept his touch light and professional as he moved on to dressing the shoulder correctly. 

“Our true natures cannot be over ridden, you cannot fight what you are forever.” It wasn’t said with condemnation but with resignation. 

“And that is why you keep coming back, to test my resolve.” John finished, it was a familiar conversation. “If my existence as a Wesen doctor bothers you so much, you know what to do about it.” 

John plastered on a professional smile and strode to the door. “All done Detective Holmes, until next time.” 

Sherlock Holmes retrieved his clothing, swiftly dressed and strode from the clinic without a backward glance but John followed him with his eyes, as did another within the waiting room.


	2. All roads lead to Holmes...

Dull

Dull 

Dull

Non-Wesen related crimes were so very Dull! They were predictable and boring and truly had no purpose other than to annoy Sherlock. 

Not that D.I. Lestrade saw things that way, but then Sherlock was surprised the D.I. managed to solve any crimes with how incredibly dense to the obvious he was, one would think that the man would have clued on by now after 10 years of investigating Wesen related crime but alas not. 

Sherlock, a Grimm by blood and by training but not by ability could tell instantly which cases were Wesen and which were not, D.I. Lestrade didn’t think far enough out of his box to even wonder at the strange crimes, bodies and general oddities which came their way. 

Sheep! The lot of them! 

But that was better than the wolves hidden in their defences, filling out the upper ranks and covering up Wesen crime. Not that Mycroft was much better, infiltrating the British Government as a Grimm and making his own survival assured through sheer position and status.

Mycroft was a force to be reckoned with, even without his ability to see Wesen. Not that a Holmes really needed that, there were other ways to tell who was a Wesen and who was not, it was the type that took a bit more work to figure out. That was the part of the puzzle Sherlock enjoyed most. 

Mummy said that Sherlock was too stubborn to let his Grimm abilities fully develop, that to him it would be like cheating or taking the easy way out and Sherlock was forced to admit he agreed. Being able to see Wesen woge from fear upon seeing him, while mildly satisfying, would take half the fun out of his detective and Grimm work. 

Some were easy to distinguish as their regular personalities reflected their Wesen stereotypically, generally the Wesen of prey were easiest though the only difficult part about their slow brutish counterparts was telling one aggressive lump from another. 

Day to day Sherlock got by through solving puzzles and human related crime for the New Scotland Yard, occasionally he found a juicy case but usually it was simply a way to pass the time and look for rogue Wesen. Now despite being a Grimm but blood Sherlock did not consider himself prejudiced against their kind, not all Wesen hunted or lost control. However, those who did needed to be removed, because once they had tasted the power that comes from releasing their inner beast it was a rare Wesen indeed who could return it to it’s cage. 

That’s where Doctor John Watson came in. Sherlock had met him when they crossed paths during a case, Doctor Watson was treating a victim of Wesen domestic violence whose spouse had turned up at the morgue. Apparently, the Victim’s brothers hadn’t taken kindly to the news of their sibling’s plight. Sherlock hadn’t killed the pair of Wesen, but he did ‘encourage’ them to turn themselves in and Mycroft was keeping close tabs on them for any warning signs for repeat behaviour. Wesen killing Wesen, especially for justifiable reason, was not a Grimm’s problem. 

As a man Doctor Watson was a highly qualified military doctor recently returned from service who, despite exceptional skill, qualification, experience and composure, had left high stakes medicine for a low paying position in a quiet doctor’s clinic. The doctor treated all patients openly and fairly, Wesen or Kehrseite it didn’t matter. This kept him very busy with Wesen and Kehrseite-Schlich-Kennen as experiences Wesen doctors, or ones that wouldn’t ask too many questions about suspicious injuries, were hard to come by. Sherlock respected John Watson the man. 

It was John Watson the Wesen he was concerned about. 

It was not unusual for Wesen, especially predatory ones, to join the military. It instilled discipline needed for their inner beasts while allowing them regular physical outlets and often company for their own kind. The problems arose when those same Wesen went to war. They would be fine until the first kill whether it be their own or the death of a comrade then, usually, they lost themselves to the bloodshed. There was no coming back for a war broken Wesen, they continued to kill until they themselves were killed usually at the hands of an enemy or a higher ranking Wesen attempting to minimise exposure. Those that did manage to keep their heads, that never rampaged, remained in the military for life. 

Mycroft, in his position As the British Government, had made an agreement with his Wesen counterpart that Military affairs, so long as they remained in the military were not ‘Grimm’ concerns. Having a Grimm overseeing things kept the Wesen aware and any warning signs were dealt with immediately. Except for Doctor Watson. 

Sherlock had yet to confirm his standing theory, but it was his belief that Doctor John Watson was a Pflichttreue, a white panther-like Wesen known to be smart, fearless, and extremely loyal. All characteristics which fit the military doctor to a tee. The man was too quiet and agile, despite his war injury, to be anything other than feline. Doctor Watson clearly felt an obligation to other Wesen, enough so to spend years and a small fortune going through medical school Before entering the military. Proud enough to do so to ensure he had the best qualifications without being handed them for subpar work or owing his skills to the military itself. Everything pointed to Pflichttreue. 

However, with the positives came the negatives. Sherlock had known well before Mycroft had confirmed, that Doctor Watson had lost himself to his inner beast while in Afghanistan. It was in the tense way he held himself, as though he were always on edge and on guard… fighting a war within that no one else could see. It was also in his eyes, crystal clear blue that held a darkness within them. 

The details were scarce because officially the event never happened but what Mycroft had been able to discover was enough to make even Sherlock queasy. 

Officially ‘Captain Watson’ had been stationed in a medical encampment near the front lines, it was risky work, but he held his command well and treated both comrade and adversary without judgement. A well-respected soldier, with a reputation on both sides which kept him protected. At least for a while. 

It was a shock, to everyone involved, when the decision was made by someone on the other side of the trenches to storm the medical encampment. It was still unclear what they were after but the official report states medical supplies were stolen after the mass slaughter of the medical teams and their patients. 

The camp was found by a military convoy a week later, Captain John Watson was not amongst the dead. Officially he was found a week later delirious and barely conscious with a partially healed, heavily infected gunshot wound to the shoulder in what remained of the enemy camp. 

This telling however left several things out, including whether Captain Watson was taken hostage or simply wasn’t as easily killed as anticipated and followed their attackers with Wesen stealth, how exactly his injury came about, and why he was found surrounded by severed heads mounted on hand made spikes. 

Sherlock and Mycroft agreed, a rare occurrence indeed, that it didn’t matter if the good Doctor had been taken to the camp or stalked his assailants. The fact was irrelevant. Neither had any doubt the John Watson was responsible for the retaliation attack on those who’d annihilated the medical camp, despite the official report stating the Doctor was too incapacitated due to the bullet wound and infection to do anything of the sort.

Destroying that many trained soldiers, and displaying their heads as a warning, was a clear sign of Wesen beast mentality. Under normal circumstances the soldier in question would have been sent on another ‘mission’ which he wouldn’t return from. Doctor Watson had been invalided home instead, released from the military and turned loose on the world. 

When Mycroft had pressed, the Wesen council had claimed that there was no evidence to say Doctor Watson was responsible or that if he was that he was not in full control. They also claimed that due to the extent of his injury he would no longer be a threat, to anyone. 

Mycroft was unable to push further than that, not without risking his position as ‘impartial’ to Wesen-Wesen dealings, but he kept tabs on the doctor anyway and was thoroughly relieved when Sherlock stepped in to take over Wesen-sitting. 

Sherlock regretted that the day would come when he’d have to kill John Watson, the man was a damn fine physician, but only a handful of Wesen could have committed such atrocities clear minded and Sherlock knew that the good doctor was not one of them.


	3. Date with the Devil... or close enough

“You realise that you don’t need to recklessly injure yourself every day to come and visit me?” John scolded as he finished stitching the slash marks across Sherlock Holmes’s back, the shoulder wound from the day before was already weeks ahead of where it should be healing wise but that didn’t make it appropriate for the man to be out fighting again. 

“Why else would I visit a physician?” Sherlock asked with a raised brow that the doctor couldn’t see but could hear in the tone alone. 

“Oh, I don’t know but you seem intent on seeing me every day. Allow your body to heal completely for a change and I’d agree to meet you outside of the clinic, I’ll even listen to you brag about your cases again.” 

“You like listening to my cases…” A statement of fact but with a hint of vulnerable question. 

“Indeed I do, what I don’t like is stitching you up while I hear about them. You may be a Grimm but you are neither indestructible nor immortal, if you’re not careful you will die a pathetic death due to overwork and poor selfcare.”

“Impossible”

“Tell me Mr. Holmes, when did you last eat. Tea and biscuits your Mrs Hudson provide do not count!” 

“Keeping tabs on me Doctor?”

“Deflecting Detective?” 

“Ack, fine. Tuesday.” John didn’t need to look at his calendar to confirm it was indeed Friday.

“Right, well then this will be our last visit Mr. Holmes.” John said with a grim finality, pulling off his blue surgical gloves with a snap, “I won’t treat patients with death wishes, I’m not that kind of Doctor.”

“Oh, don’t be so melodramatic…” Sherlock stood but when his eyes met the Doctors he paused, there was something he couldn’t read in them and Sherlock prided himself on reading people. “Would dinner suffice?” 

John nodded, it would at least be a start with the too thin Grimm. 

“Fine, I will meet you here at 5:30.” Sherlock was already dressed and preparing to leave the room when John’s mind clicked over that statement. 

“Sorry…?” 

“Oh, do keep up Doctor, Dinner. Your finish your shift at 5 o’clock so I will see you at 5:30, that should be plenty of time to finalise things for the day.” 

“Yes, but…”

“I will see you this afternoon, try not to be late Doctor.” 

Sherlock did not wait for John’s response but swept out of the office as was his usual practice and left a stunned Physician in his wake. 

“Oh… well that’s different.” John spoke aloud before shaking himself from his stupor to resume his work, he supposed he had said he would meet the man outside of work if he practiced better self-care… John just hadn’t expected Sherlock to take the jibe sincerely. 

That being the case the day passed in unprecedented swiftness, though the ribbing he got from the other medical staff when they saw Sherlock Holmes waiting for him outside had John flustered when he greeted the man. 

“Mr. Holmes.” John nodded. 

“Sherlock.” Those intense eyes settled on John and regarded him fully. 

“Sorry…?” 

“We are not meeting in a professional sense, there is no need for formalities John.” John was surprised by how nice his name sounded coming from those perfectly moulded lips. “How do you feel about Italian?”

John nodded mutely and was swept off to a restaurant Sherlock frequented, when he was in the mood to eat that is, and Sherlock did indeed brag about his past cases and mused aloud on his current one. It was fascinating to listen to the man speak, to be allowed the slighted glimpse of how such a brilliant mind works was a rare thing indeed. At least until Sherlock began to outline his intention to involve John in his latest case. 

“You see the Yard are out of their depth, most have no idea that the link between the victims is that they were all Wesen and those that do are only getting in the way. That’s where you come in Doctor; I need an expert on Wesen medicine to assist me to try and figure out what drug they are using. So far it has successfully killed six that we are aware of, all different kinds of Wesen both prey and predator alike, we don’t know how they’re spreading it or even what it is to combat it. I would appreciate your expertise in this.” 

It was said so casually that John almost missed the fact that this was the first time Sherlock, in their months of visits at the clinic, had ever asked for something and not simply demanded or manipulated to get his own way. Would wonders never cease? 

“I understand, I would be happy to help”

“Brilliant, then let’s be off…” Sherlock practically leapt to his feet, threw on his coat, nodded to the owner and flew out the door before John could blink. 

John was still sitting there, stunned and opened mouthed, when Sherlock returned a few moments later with an impatient huff. 

“Are you going to join me Doctor Watson or not?” 

John scrambled to his feet, much less gracefully than he should have all things considered, and ran out the door after the Grimm Detective and so the whirlwind that was to be their friendship began.


	4. Trust issues

John stood at the window of the neighbouring building, he watched Sherlock pick up the pill and his blood ran cold. Why would a man, A Grimm, as smart as Sherlock Holmes take the gamble against a madman with nothing to lose? Why didn’t he simply knock the Kehrseite out and be done with it, the gun would not be a real threat but whatever concoction was in those pills clearly was. The taxi driver we Kehrseite, he wasn’t even Kehrseite-Schlich-Kennen and thus aware of Wesen. Someone else was pulling the strings, picking the targets and calling the shots and it left a bad taste in John’s mouth that they were being lead, so easily, by the nose. 

Though perhaps not as easily as their puppeteer planned, it seemed he’d not accounted for John’s presence and had then been forced to make rushed contingencies. So John had be lead, by scent, to another part of this damnable building so as to be unable to interfere, he could smell ‘Smug’ in the air around him. Clearly they hadn’t expected much from John, few people ever did. Many forgot he was Wesen at all, let alone what kind. Mild mannered, gentle, pacifist, Doctor Watson would never be considered a threat. He certainly wouldn’t be carrying an unregistered fire arm and if he did then he wouldn’t possibly know how to use it despite his years in the military. He was a Doctor after all. 

So when the New Scotland Yard came round the next morning, asking for his whereabouts at the time the Taxi Driver had been shot and Sherlock coincidentally saved John simply had to look at them, bundled up in one of his least threatening jumpers, with a mildly confused frown before they apologised profusely and explained that it was “Only a formality and nothing to worry about, sorry to bother you Doctor.” 

John had smiled, explained that after discussing with Sherlock and their Inspector Lestrade about the phone he’d thought it best to return to his own apartment instead of waiting at 221B Baker street for news from Sherlock at which point he’d returned to his new friend’s apartment to ensure he was safe and well. The officers wrote that down, John offered them tea, they politely declined before scurrying off and Sherlock had scoffed. 

“The think you’re perfectly placid, as threatening as that awful jumper you’re wearing” Sherlock claimed from his lounging position on his sofa, fingers steepled together on his chest, eyes closed in apparent thought. “They have no idea what you’re capable of…”

“And you do?” John asked with a raised brow, turning to the detective. 

“I’m beginning to. Would you tell me if I asked?” It didn’t take a genius like Sherlock Holmes to know what the Grimm was asking. 

“No. It’s not a time I want to think back on.” John answered, turning to busy himself baking tea in the Grimm’s barely habitable kitchen. 

“Indeed” He could practically hear the nod, “then to satisfy my curiosity will you tell me what you are?” 

“I am a Doctor Sherlock, that’s all that you need to know.” 

“You killed someone you know,”

“Allegedly…” John agreed

“An unarmed Kehrseite, strictly speaking I should kill you…” 

“I suppose so…” John said playing with the string of the teabag as the jug boiled. 

“Thank you.” 

John smiled as he poured the milk, “Just make sure it wasn’t for nothing okay?” 

Sherlock nodded and later that week John moved in to the upstairs bedroom at 221B Baker Street. 

Sherlock would say it was to keep an eye on the time bomb Wesen, that this incident proved the risk he posed unsupervised. John would say he was becoming a live-in babysitter but that it was better than Sherlock pestering him at the clinic every day but what they said didn’t matter.

The truth was that they trusted each other in a way neither had been allowed before and neither wanted to risk losing that, though they would never admit it. Though admit it or not, the fact had not gone unnoticed by some.


End file.
